This invention relates to structural members. This invention also relates to erosion control systems, and more particularly, to a composite of substantially parallel elements connected therefore.
In a previously filed application, an invention was disclosed relating to rods and shafts which are suitable for use in the construction of tapered and parallel edged fishing rods, golf shafts, yacht masts, sailboard masts and the like.
Fishing rods, golf shafts, yacht masts, sailboard masts, and the like are generally constructed of fibre-resin composites or metal in the form of solid rods or tubes. Hollow composite rods are accepted as being superior in performance to solid composite rods in light weight uses but they are delicate and easily damaged. Solid metal rods and metal tubes are generally inferior in flexural characteristics to the composite rods. It will be apparent to the skilled person that the teaching of rod or shaft construction in the above arts may be effectively applied to other heavier, industrial or civil engineering uses as well.
Tapered, tubular composite rods require expensive, accurately ground metal mandrels to produce the taper necessary for the desired performance and there are considerable difficulties in manufacturing with uniform wall thickness. An attempt to overcome to some extent the problems associated with tubular rod manufacture from composite materials is the subject of U.S. Pat. Nos. 4,582,758 and 5,229,187 (referred to herein respectively as Bruce and Walker and McGinn), the enabling teaching of which are incorporated herein. Both patents relate to the provision of rods of polygonal cross-section formed by a plurality of elements of certain geometrical cross-section. Bruce and Walker describes that each of the elements has a base part of a fibre reinforced plastic material and an apex of part of a rigid plastic material foam.
McGinn, on the other hand, adopted a method of using T-sections made from fibre reinforced plastic material. The method by which the joints of the top ends of T-sections in McGinn are joined is shown in FIG. 5 of that patent. It is seen that the top ends of the T-sections must be molded or machined to a relatively small tolerance to accommodate matching of the several faces of the T-sections to each other. Both these rods, while they solve wall thickness variation problems and obviate the need for expensive mandrels for forming are difficult to make in the required thickness.
Bruce and Walker experience difficulties in the required stiffness for heavy load application such as are encountered in deep sea fishing and similar application without resorting to excessive composite wall thickness. The technology applied by McGinn addresses the stiffness required in heavy load application, but the mere nature of this technology reduces the ability to make the rods flexible for fly rod application in the various line weights required. Neither invention has adequately addressed the problem of torque encountered in small structures such as golf shafts.
The problem is severe in the case of Bruce and Walker. The McGinn technology has gone some way to addressing this problem with sufficient torque being removed from fishing rods to make them user acceptable. However, the problem of torque is highlighted when both products are used as golf shafts. Any torque in the shafts alters the angle of the golf club head when it comes in contact with the ball, which is unacceptable to the playing golfing public.
It is therefore one object of the present invention to provide a rod, shaft, etc., which obviates or at least minimizes the aforementioned disadvantages of conventional rods and those of Bruce and Walker and McGinn.
Erosion prevention and control systems are useful for minimizing erosion around underwater structures, including pipes, pilings, bridges and cables, that rely on the seabed for support and also for minimizing coastal shoreline and beach erosion, as well as retaining the finer silts and muds of wetlands. Methods and devices for preventing underwater bed and shoreline and wetlands erosion are known. Some of these devices, such as breakwaters and groynes, although relatively time intensive and expensive to install, are effective in minimizing shoreline erosion and are generally constructed from rock, concrete, rubble mounds and other hard body materials. Other devices, primarily used for erosion control on seabed structures, operate by increasing viscous drag on the underwater current, thereby reducing the velocity of the current and of the particulate transported by the current. This causes some of the particulate to settle out of the current and to be deposited in or around the erosion control system. The precipitated particles form a berm in and around the erosion control system. Typical of those devices that increase viscous drag on the current are buoyant frond elements or artificial seaweed or some other viscous drag element. The viscous drag elements are generally secured to the a silted surface (i.e., a seabed or riverbed) via some type of anchor line.
As the cross sections of the hydraulic passages in the viscous drag materials decrease, the amount of drag on the viscous drag elements increases. The structural strength of such materials must be increased to withstand the drag required which is sufficient to disrupt laminar flow of the silt bearing or erosion causing water flow. The ability of the viscous drag elements in prior art appear to rely on greater weight than necessary to obtain the desired sediment precipitation. However, these factors lead to the enhanced ability to build higher berms of precipitated particles. For coastal shoreline applications it is essential to have high berms which will form submerged, wide-crested breakwaters which, optimally, reach a height of 80% of the depth of the water. For wetlands sediment retention, the extremes of hurricane driven water flows to extremely low and constant velocity water flows must be accommodated to retain sediment.
With respect to sediment in having substantially the grain size of sand beaches, waves travel by pressure and move in an oscillating fashion to strike and wash across the beach surface. The forward and backward motions of the water, moving just above the bottom of the sea, are unsymmetrical, with the forward motion being stronger and of shorter duration than the backward motion. The carrying capacity for suspended solids in the moving water is generally proportional to the velocity of the flow. That velocity of flow can be regulated or influenced by environmental and/or man-made barriers. Thus, when the velocity of the flow is sufficiently reduced, deposition or precipitation of suspended solid matter occurs.
The best protection against shoreline erosion is a wide beach since that environment causes the waves to break, thereby dissipating the wave energy before the erosion of the shoreline can occur. Normally, beaches grow seaward by deposition of sand from longshore currents and new sand brought from offshore by the formation of a ridge and runnel system perpendicular to the beach. Long waves of small amplitude serve to replenish the shoreline, while short storm waves of high amplitude erode the shoreline.
Experience has shown that natural sandbars provide excellent protection against destructive wave forces. Consequently, attempts have been made to simulate sandbar action by constructing artificial barriers parallel to the shoreline. Such barriers have been unsuccessful because high velocity water currents typically scour and undermine their foundations, causing the barriers to fail and to lose their effectiveness.
The present invention is a general structural member assembly. Two embodiments of a basic structural unit of the present invention have two adjacent shafts, both further having a cross sectionally triangular shape with a longitudinal side completely or substantially mostly removed. The xe2x80x9copenxe2x80x9d side, i.e., the side completely or substantially mostly removed, in cross section presents two xe2x80x9clegxe2x80x9d ends, i.e., the ends distal to the vertex of the longitudinal sides that at structurally intact and maintain the vertex of the two solid sides and such that the legs are approximately equal in length. The leg ends are formed or machined such that they present two outward surfaces generally parallel to the open face of a first adjacent shaft. The outward surfaces of the leg ends are then positionally fixed, albeit with some flexible movement in some embodiments, to generally have a parallel and longitudinal interface with the longitudinal outside edges of a solid side of a second shaft. Additional shafts may be added in this open side opposed to solid side basic assembly unit to form a single joined polygonal shaft assembly where all of the open sides are enclosed with a solid side, the additions proceeding in a circular fashion to form a polygonal cross section of exceptional strength and torsional resistance. Where a more extensive structure is desired, additional whole or partial sections of these joined polygonal shafts may be joined along one or more of their solid faces longitudinally along the solid faces of a first joined polygonal shaft, or portion thereof, at least preserving one basic structural unit of an open side positionally fixed to a closed side.
In the first of the two above embodiments, the open side completely lacks any portion of the longitudinal face of the triangular cross section of the adjacent shafts. The second of the two above embodiments comprises two short opposing extensions from the ends of the solid sides without such in the first embodiment, such that a short portion of the open side is formed along those legs to improve flexing strength.
In a third embodiment of a basic structural unit, two adjacent shafts also have open sides, a first adjacent shaft having solid sides and legs similar to those of the first embodiment except that an outside facing solid side has a cross section first length that is longer than that of the joined polygon enclosed solid side by about the thickness of a solid side. A second adjacent shaft also has an outside facing solid side of about the same cross section length and leg surface as that of the first adjacent leg. The joined polygon enclosed solid side of the second adjacent shaft also has the same length as its outside facing solid side, although it is further extended from its leg end in a direction such that the leg surface of the shortened leg of the first adjacent shaft presses in a force transmitting connection on an inside surface of the extension of the second adjacent shaft in an assembled arrangement as a basic structural unit. The assembled and combined cross section length of the shortened joined polygon enclosed solid side of the first adjacent shaft with the thickness of the extension of the joined polygon enclosed solid side of the second adjacent shaft then presents an outside surface of the extension as a leg surface effective with the leg surface of the outside facing solid side of the first adjacent shaft to then fixedly oppose the outside surface of a joined polygon enclosed solid side of another adjacent shaft such as that of the second adjacent shaft.
It is a further improvement of the present three basic structural units to provide single layer or laminar binding around the outside facing solid sides of a joined polygonal shaft assembly without any further securement, gluing, welding, bolting, soldering or the like between the adjacent shafts such that the adjacent shafts remain in positions sufficiently fixed to effect the support required of their application. This wrapped, un-secured embodiment is useful when sliding flexure of the adjacent shafts are desired, especially when a type of bending or twisting force is not so great as to break down the surrounding support.
It is a further improvement of the present three basic structural units to provide a single bonded axial connection to the central axis of the joined polygonal shafts, whereby the bonding may be accomplished with glues, expoxies, weld connections, solder or other methodologies (such as bolting and piercing/riveting methods) appropriate for securement of the central axis formed by the zone of leg ends of the joined polygon enclosed solid sides. Such joined polygonal shafts may then be bundled and secured together or with other longitudinal supports about their periphery such as described in the previous paragraph.
It is a further improvement of the present three basic structural units to provide bonding as described in the previous paragraph is provided only for the interface between the leg surface of the outside facing solid side and the abutting vertex zone of the joined polygon enclosed solid side of the adjacent shaft. A joined polygon shaft of this embodiment thus comprises an outer edge of longitudinally bonded adjacent shafts while leaving free for sliding movement the zone of leg ends of the joined polygon enclosed solid sides during flexing or torsional movement.
It is a further improvement of the present invention to combine the wrapping securement, central axis or outside facing seam bonding in combination with each other to obtain specific performance characteristics of flexing and torsional response. For example, the combination of a wrapping securement and the central axis bonding permits some slidable flexion in the interface between the leg surface of the outside facing solid side and the abutting vertex zone of the joined polygon enclosed solid side of the adjacent shaft while stiffening the overall structure with a non-bonding sleeve under the stiffening wrapping securement.
It is yet another embodiment of the present invention to form joined polygonal shafts with at least three or more sides. Any of the basic structural units are easily adapted to form joined polygonal shafts of any number of cross section outside solid sides so long as that number is three or more.
Additional inventive supports for the basic structural units comprise inserts into or fills for the void between the outer face of a joined polygon enclosed solid side of a first adjacent shaft and the inside faces of a the outside facing solid side and a joined polygon enclosed solid side of a second adjacent shaft, forming a longitudinal void with a roughly triangular shape. Longitudinal support inserts or fills into this void may have a cross section shape of a plane, triangle, circle (or oblate), separate solid rods, solid fill (urethane foam, epoxy, solder or metal), or fusible structurally supportive material. Appropriately smaller adjacent shafts of the present invention are also adaptable to be inserted alone or in a nesting relationship as longitudinal support for insertion into such a longitudinal void. Another class of inventive supports comprise planar inserts longitudinally interposed between and along the outer face of the joined polygon enclosed solid side of a first adjacent shaft and the leg surfaces of a second adjacent shaft. It has been found in prototype models of this planar insert embodiment that very thin, even flexible plastic material may comprise the basic structural unit while providing a planar insert bonded to the outer face of a joined polygon enclosed solid side that creates a joined polygon shaft of superior strength.
The basic structural units of the present invention may be used in such a wide number of applications that the types of additional supports described in the preceding paragraph may be applied separately or in combination along the length of any single longitudinal void. For example, in an antenna, ship mast or hull, or building joist where variable strength, flexibility and resistance to torsion may be desirable, a nested set of smaller adjacent shafts in one section of the longitudinal void may be easily reduced to an identical set of such supports less the innermost nested adjacent support shaft.
In an embodiment using the structural member of the invention in an assembly for soil or sediment retention and accumulation, the structural member of FIG. 8 comprises a lattice type material, preferably a swaged or expanded metal grating. Such metal grating is well known in the art for supporting persons or similar loads. It is known that such grating is often specified with respect to the grate opening formed on expansion of a slotted metal sheet. The grate openings intended for use in this embodiment are from xc2xc inch to 2 inches, and more preferably from about xc2xd inch to 1 inch. Upon first consideration, the open, apparently non-sediment retaining structure of the swaged or expanded metal grating would cause the skilled person to disregard such materials for sediment retention or accumulation. However, the mere skilled person does not have the benefit of knowledge of the present structural member as shown in FIG. 8. The structural member of FIG. 8 of this embodiment is optimally joined horizontally side by side with other such members to form a first layer and may receive on its upper side and in parallel relationship to the first layer a second or greater number of layers of such structural members, thereby creating a sediment retaining or accumulating stacked assembly. It is preferred that the stacked assembly be anchored in any of several methods for securing the stacked assembly such that it will generally lie with its structural members normal to the flow of water across a sediment surface, i.e., if on a beach, the structural members would generally be parallel with the coastline at that location. Such anchoring comprises methods such at securing each end of the stacked assembly with a rope or ropes or chain or chains to single or multiple posts driven into the subsurface sufficiently deep to maintain the desired relationship of the stacked assembly to the water flow through the several types of wind and weather to which the sediment surface is exposed. The stacked assembly has proven effective in causing precipitation and capture of sand and sediment from ocean waves sufficient to cause berm formation on an open beach. Such a result is highly surprising in light of the teaching in the prior art to form substantial wall structures to reach substantial heights or height limited structures of lesser bulk. The present invention permits formation of a stacked assembly with almost no height limit, as the structural strength contributed by the structural members permits the relatively open frame structure of the swaged or expanded grating. In a specific experiment, a structural member was formed with an element cross section side of about 6 inches and using axc2xd inch swaged metal grate to form all the elements of the structural member as in FIG. 8. A single layer of the structural members was subjected to a water flow from a 3 inch fire hose supplied from a typical water mainxe2x80x94the single layer prevented any pressurized water flow from passing to the other side of the single layer. The swaged metal grating provides twisted surfaces on the grating forcing laminar flow into locally turbulent regions that then impinge on each other without requiring wide and substantial surface area that the skilled person would expect to be required for obtaining the objects of this stacked assembly embodiment.